This invention generally relates to fuel vapor recovery systems and more particularly to a filler neck assembly and tank inlet configuration therefor that provides a vent path for the recovery of fuel vapor generated in the operation of filling a fuel tank by a dispensing nozzle having means for drawing the vapor back into the source supply of fuel.
In the activity of refueling tanks, whether of the vehicle type or of the stationary above or below ground types, fuel loss in the form of vapor is of increasing concern, not only because of its polluting affect and obvious hazard but also because of the waste. In this circumstance, manufacturers have concentrated efforts in the development of vapor recovery pumps and nozzles and numerous type of filler tube venting arrangements which connect between the tank being serviced and the entry port accepting the fuel delivery nozzle. These venting arrangements have usually included a vent tube that is either connected externally of the filler tube or else mounted within the bore of the filler tube. In the case of an external vent tube, multiple connections are required at the entry port and also at the tank and this arrangement further increases the cost and makes the vent vulnerable to damage. In the case of an internal vent tube ie. mounted within the bore of the filler tube, the vent is subject to being blocked by the rising fuel in the tank while also increasing the manufacturing cost by reason of the manner of affixing the vent within the filler tube.
Descriptions of these prior art devices and techniques may be had by way of the following U.S. Pat. Nos. 3,187,936 (06/08/65 ) to K.D. Downing; 3,369,695 (02/20/68) to L.D. Johnson; 4,009,739 (03/01/77) to D. J. Weatherford; 4,122,968 (10/31/78) to L.A. Germain; and 4,135,562 (01/23/79) to Martineau et al.
This invention expands the prior art as exemplified in my U.S. Pat. No.4,122,968 issued Oct. 31, 1978 which describes a tube-within-a-tube concept for fuel vapor recovery. The filler neck of the subject patent comprises a fuel delivery tube having a plurality of ribs on it's outside surface and which is connected into the inside of a conventional tank entry nipple. A sleeve tube is slipped over the fuel delivery tube in a coaxial relationship and is connected at one end to the fueling port and at the opposite end to the outside of the tank entry nipple. The relationship between the two tubes and the tank entry nipple is such that a vapor path exists in the valleys defined by the ribs and thus the fuel vapor that is generated in the filling of the tank may be drawn up through the path provided between the tubes by a nozzle having means for returning the vapors to the source supply.
An aspect of the present invention therefor is to provide a filler neck assembly of the coaxial tube-within-a-tube configuration wherein the assembly may be applied to installations requiring a complex curvature of the tubes such as for example within the bodywork of a vehicle. In this type installation the outer tube will be formed or molded to the required complex curved shape while the bore configuration is such as to readily receive a fuel delivery tube that is connected into the tank entry nipple. A further aspect of invention also proposes a tank entry nipple and inlet configuration that simplifies installation of the filler tube assembly while also providing a secure crashworthy connection.